Cytology & Effusions Flashcards
(37 cards)
What are the 3 major types of samples used for cytology?
- FNA (22G needle and 5cc syringe) and impression smears
- washes - prostatic, transtracheal
- fluids - peritoneal, pericardial, pleural, synovial, CSF, bronchoalveolar lavage, urine
What are the pros to running cytology?
- minimally invasive
- fast, simple, inexpensive
- better cellular detail than histopathology
- can observe infectious organisms
What are some cons to running cytology?
- cannot evaluate tissue architecture
- poorly exfoliating lesions, like sarcomas, are difficult to observe
- can rupture cells
- can’t always be used to make a diagnosis
- difficult to differentiate reactive mesenchymal cells from neoplastic cells
What are the 3 major components of a cytological evaluation?
- overall cellularity - high vs. low (low cellularity samples make interpretation difficult)
- cell components/types - uniform populations vs. mixed
- background components - blood, proteinaceous material, organisms
(best to send organ aspirates and bone marrows to pathologists)
What is the first approach to evaluating a cytology sample?
scan the slide at low magnification (10x) and find cellular area where cells are well spread out and intact
- where the appearance of nuclei and cytoplasm of individual cells can be evaluated
What is done on cytology evaluations at high magnification (50x, 100x oil)?
characterizing cells - normally found in the location of the sample?
- types of inflammatory cells
- organisms presence
- non-inflammatory cells: epithelial, mesenchymal, round
- do non-inflammatory cells exhibit criteria of malignancy
How are inflammatory lesions classified?
- suppurative = neutrophils
- mononuclear = lymphocytes, plasma cells, macrophages
- histiocytic/granulomatous = macrophages
- pyogranulomatous = neutrophils + macrophages
- eosinophilic
- lymphoplasmacytic = lymphocytes + plasma cells
- mixed
What is evaluated on suppurative inflammation?
neutrophil morphology —> degeneracy (larger than normal with distended vacuolated cytoplasm and a slightly swollen enlarged nucleus)
- if yes, search for bacteria
What infectious cause of suppurative inflammation? What if an eosinophilic component is also seen?
bacterial infection —> especially if there are degenerate neutrophils (septic suppurative)
parasitic or allergic component to inflammatory response
What are 4 possible non-inflammatory causes of suppurative inflammation?
- severe irritants/chemicals - uroperitoneum, bile peritonitis
- immune-mediated inflammation
- trauma
- ruptured follicular/epidermal cysts
What are 3 infectious causes of histiocytic/granulomatous inflammation?
MACROPHAGES
- protozoa - Leishmania, Toxoplasma
- atypical bacteria - Mycobacteria, Nocardia, Actinomyces
- fungi - Histoplasma, Blastomyces, Cryptococcus, Coccidioides
When is fungal infection especially indicated with histiocytic/granulomatous inflammation?
if epithelioid macrophages and/or multinucleated giant cells are found
What are 3 non-infectious causes of histiocytic/granulomatous inflammation?
- foreign bodies/materials - plants (grass awns), vaccine adjuvants
- acral lick dermatitis (lick granuloma)
- late stage chronic/resolving inflammation
What makes up pyogranulomatous inflammation? What are the 3 most common causes?
50-70% neutrophils, 30-50% mononuclear cells (macrophages, multinucleated giant cells, lymphocytes, plasma cells, mast cells)
- foreign body
- fungal infections
- chronic/resolving suppurative inflammation
What are 2 infectious causes of eosinophilic inflammation?
- parasites: Dracunculiasis, Demodicosis, Dirofilaria, Dermatophytes
- oomycosis and algal organisms: Pythium, Prototheca
What is commonly also seen with non-infectious eosinophilic inflammation? What are 3 common causes?
mast cells and basophils
- eosinophilic plaque/granuloma
- flea bite or food allergies, atopy
- arthropod bite reaction
What are the 3 categories of neoplasia? Why is cytological criteria evaluated?
- epithelial
- mesenchymal
- round
detects criteria of malignancy to determine if the neoplasia is benign or malignant (NOT reliable for round cell tumors)
What are the 6 criteria for malignancy?
- anisocytosis - variation in cell size between cells of the same origin
- anisokaryosis - variation in nuclear size
- immature chromatin
- multinucleation
- abnormal mitotic figures
- nucleolar changes - enlarged, prominent, multiple, variably shaped nucleoli
What are the 3 main characteristics of epithelial cell tumors?
- tightly cohesive clusters
- polygonal to round
- distinct intercellular junctions
What are the 6 categories of round cell tumors?
- plasma cell
- histiocytoma
- lymphoma
- transmissible venereal tumors
- mast cell tumors
- melanoma
What are the 4 major characteristics of round cell tumors?
- exfoliate well, samples are highly cellular
- round shape/borders
- can be in clusters or individually distributed
- criteria of malignancy are not reliable
What are the 3 major characteristics of mesenchymal tumors?
- exfoliate poorly, better suited for histopathology
- distributed both in clusters and individually
- wispy, attenuated to stellate, abundant cytoplasm
What are the 4 basic parts to fluid analysis?
- color, clarity
- cell count
- total protein
- cytological evaluation - differential cell count, cell morphology, organisms
additional tests may be indicated
How should fluids be collected? What if they’re being cultured? How are they sent out?
in an EDTA (purple top) tube to prevent clotting
collect a separate aliquot from into a red top tube, since EDTA is bacteriostatic and can cause false negatives
since the fluid will likely not be process within 2 hours, make direct smears and send a purple top AND a red top tube to the lab
